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      <title>Pipeline和Handler链 - 交互式测验</title>
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    </head>
    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>Pipeline和Handler链 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
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                    <div id="question-container">
                      <p id="question-text"></p>
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                    <div id="hint-container" class="hint-container"></div>
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                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
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                  <button id="next-btn" class="nav-btn">下一题</button>
                </div>
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      </div>

      <script>
        const quizData = [
  {
    "question": "在Netty中，Pipeline（管道）的设计主要实现了哪一种经典的设计模式？",
    "options": [
      "观察者模式 (Observer Pattern)",
      "责任链模式 (Chain of Responsibility Pattern)",
      "工厂模式 (Factory Pattern)",
      "单例模式 (Singleton Pattern)"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档中明确指出，Pipeline是由一系列Handler组成的链条，事件会依次在链中传递和处理。这种将请求的发送者和接收者解耦，并使多个对象都有机会处理请求，将这些对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它为止的模式，正是责任链模式的典型实现。",
    "source": "文档中「什么是Pipeline？」部分",
    "hint": "文档描述Pipeline是一个由多个处理节点组成的链条，事件会沿着这个链条传递。"
  },
  {
    "question": "根据Netty的Handler分类，哪种类型的Handler专门负责处理即将发送到远程对端的数据或事件，例如数据编码？",
    "options": [
      "Inbound Handler (入站处理器)",
      "Duplex Handler (双工处理器)",
      "Outbound Handler (出站处理器)"
    ],
    "correctAnswerIndex": 2,
    "explanation": "Outbound Handler（出站处理器）负责处理向外发送的数据和事件。当应用程序需要将数据发送给客户端时，数据会流经出站处理器链，进行编码、日志记录等操作。入站处理器则处理相反方向的事件，即从网络接收到的数据。",
    "source": "文档中「Handler的类型」部分",
    "hint": "思考一下数据流向：是从应用程序“出去”到网络，还是从网络“进来”到应用程序？"
  },
  {
    "question": "在文档提供的Echo服务器代码示例中，`EchoServerInitializer`类的核心职责是什么？",
    "options": [
      "绑定服务器端口并启动服务",
      "创建用于处理连接和I/O操作的线程池",
      "为每一个新建立的客户端连接初始化其专属的ChannelPipeline，并向其中添加处理器",
      "作为最终的业务处理器，将接收到的消息直接写回客户端"
    ],
    "correctAnswerIndex": 2,
    "explanation": "代码解析部分指出，`ServerBootstrap`通过`.childHandler()`方法指定了`EchoServerInitializer`。这个类的`initChannel`方法会在每个新的客户端连接（SocketChannel）被创建时调用，其主要任务就是获取该连接的`ChannelPipeline`，并为其配置所需的Handler（如此例中的`EchoServerHandler`）。",
    "source": "文档中「示例：Echo服务器的Pipeline和Handler链」的「代码解析」部分",
    "hint": "这个类名中的 `Initializer`（初始化器）暗示了它的主要作用。"
  },
  {
    "question": "以下哪项不是文档中提到的使用Pipeline和Handler链架构所带来的好处？",
    "options": [
      "清晰的职责划分，使代码易于维护",
      "自动实现跨多台服务器的负载均衡",
      "灵活的扩展性，可以动态增删功能模块",
      "高效的事件处理机制"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档中列举的好处包括：高效的事件处理、灵活的扩展性、清晰的职责划分和解耦合。而“自动实现跨多台服务器的负载均衡”属于分布式系统架构或负载均衡器的功能，并非单个Netty应用内部Pipeline和Handler链架构直接提供的能力。",
    "source": "文档中「为什么要使用Pipeline和Handler链？」部分",
    "hint": "思考一下Pipeline和Handler是解决单个应用内部的问题，还是解决多个应用实例之间协同工作的问题。"
  },
  {
    "question": "在Netty的`EchoServerHandler`示例中，`ctx.writeAndFlush(msg)`这行代码执行的操作是什么？",
    "options": [
      "将消息传递给Pipeline中的下一个Inbound Handler进行处理",
      "将接收到的消息原样写入到出站处理流程中，最终发送回客户端",
      "在服务器控制台打印接收到的消息内容",
      "关闭与客户端的连接"
    ],
    "correctAnswerIndex": 1,
    "explanation": "在Handler中调用`ChannelHandlerContext`的`writeAndFlush`方法会触发一个出站（Outbound）事件。这个事件会从当前Handler开始，在Pipeline中向前（向头部）传播，经过所有Outbound Handler的处理，最终将数据写到Socket通道中发送给对端。在此示例中，它实现了将接收到的消息“回声”给客户端的功能。",
    "source": "文档中「示例：Echo服务器的Pipeline和Handler链」的「代码解析」和「Pipeline与Handler的执行流程」部分",
    "hint": "`writeAndFlush`是一个组合操作，它意味着“写入数据”并“冲刷缓冲区”，通常用于发送数据。"
  },
  {
    "question": "根据文档描述，Netty的`ChannelPipeline`在整个事件处理流程中扮演了什么核心角色？",
    "options": [
      "直接负责网络数据的物理读写",
      "作为Handler链的容器，负责事件的拦截和有序传播",
      "管理和分配执行任务的线程（EventLoop）",
      "仅用于处理网络连接的建立和关闭事件"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档的核心作用部分明确指出，Pipeline的核心作用是“事件传递”，它负责将网络事件（如数据读取、连接建立等）传递给链条中的每个Handler进行处理。因此，它是一个管理Handler并确保事件在其中有序流动的核心协调者。",
    "source": "文档中「Pipeline的核心作用」和「Pipeline的工作原理」部分",
    "hint": "Pipeline本身不处理具体的业务逻辑，而是像一条流水线一样，组织和调度流水线上的工人（Handler）。"
  },
  {
    "question": "如果一个网络应用需要先对接收到的原始字节流进行解码（如JSON解析），然后再执行业务逻辑，这两个操作应该如何安排在Pipeline中？",
    "options": [
      "将它们放在一个单独的Outbound Handler中",
      "解码器和业务逻辑处理器都应该是Outbound Handler",
      "解码器应该是Inbound Handler，并且应该放在业务逻辑处理器的前面",
      "业务逻辑处理器应该放在解码器的前面，先处理再解码"
    ],
    "correctAnswerIndex": 2,
    "explanation": "处理从远程接收到的数据属于入站（Inbound）事件。数据处理的顺序至关重要：必须先将原始的字节流通过解码器（一个Inbound Handler）转换为应用程序可以理解的对象（如Java对象），然后才能将这个对象传递给下一个Inbound Handler进行业务逻辑处理。因此，解码器Handler必须位于业务Handler之前。",
    "source": "文档中「Handler的类型」和「Pipeline的工作原理」部分",
    "hint": "想一想数据处理的逻辑顺序：是先解码成看得懂的东西，再进行处理，还是反过来？"
  }
];
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            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

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                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
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                '<div class="score-card">' +
                '<h3>错误率</h3>' +
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                '<div class="score-card score-details">' +
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                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
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                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  